diff --git a/build/scripts/Targets/TargetDescriptionFiles/AVR8/Signature.php b/build/scripts/Targets/TargetDescriptionFiles/AVR8/Signature.php
index 22aba3a8..4d6e3d45 100644
--- a/build/scripts/Targets/TargetDescriptionFiles/AVR8/Signature.php
+++ b/build/scripts/Targets/TargetDescriptionFiles/AVR8/Signature.php
@@ -13,9 +13,10 @@ class Signature
             throw new \Exception("Cannot generate hex string of incomplete AVR8 target signature.");
         }
 
-        return '0x' . substr('0' . dechex($this->byteZero), -2)
+        return '0x' . strtoupper(
+            substr('0' . dechex($this->byteZero), -2)
             . substr('0' . dechex($this->byteOne), -2)
             . substr('0' . dechex($this->byteTwo), -2)
-        ;
+        );
     }
 }
diff --git a/build/scripts/Targets/TargetDescriptionFiles/Services/ValidationService.php b/build/scripts/Targets/TargetDescriptionFiles/Services/ValidationService.php
index 34c4b112..e99211c3 100644
--- a/build/scripts/Targets/TargetDescriptionFiles/Services/ValidationService.php
+++ b/build/scripts/Targets/TargetDescriptionFiles/Services/ValidationService.php
@@ -63,13 +63,6 @@ class ValidationService
 
         if (empty($tdf->addressSpaces)) {
             $failures[] = 'Missing address spaces';
-
-        } elseif (count($tdf->addressSpaces) > 256) {
-            /*
-             * We store address space IDs in an std::uint8_t - which should be more than enough (I don't think we'll
-             * ever support a target with more than 256 address spaces).
-             */
-            $failures[] = 'Too many address spaces (' . count($tdf->addressSpaces) . ')';
         }
 
         $processedAddressSpaceKeys = [];
diff --git a/build/scripts/Targets/TargetDescriptionFiles/Services/Xml/XmlService.php b/build/scripts/Targets/TargetDescriptionFiles/Services/Xml/XmlService.php
index 76782b4f..df4fa085 100644
--- a/build/scripts/Targets/TargetDescriptionFiles/Services/Xml/XmlService.php
+++ b/build/scripts/Targets/TargetDescriptionFiles/Services/Xml/XmlService.php
@@ -11,6 +11,7 @@ use Targets\TargetDescriptionFiles\TargetFamily;
 require_once __DIR__ . '/FromXmlService.php';
 require_once __DIR__ . '/ToXmlService.php';
 require_once __DIR__ . '/../../TargetDescriptionFile.php';
+require_once __DIR__ . '/../../AVR8/Avr8TargetDescriptionFile.php';
 
 require_once __DIR__ . '/Exceptions/XmlParsingException.php';